I. Field of the Invention
The present invention relates generally to lift mechanisms for automobile trunks, and, more particularly, to power-operated lift and presenting mechanisms for use in assisting persons loading and unloading heavy and bulky articles to and from trunks of automobiles. Still more particularly, the invention relates to power-operated lift and presenting mechanisms, preferably of the portable type that can be put into an automobile trunk to translate a heavy and bulky article over the rear wall of an automobile trunk from a cart or the like, lower the article down into the trunk so that the lid may closed, subsequently lift the article up out of the trunk when the lid is opened, and translate the article back over the rear wall to be loaded onto a cart or the like.
II. Problems Solved by the Invention
As if designed by Aladdin's genie, the luggage compartments or trunks of many modern automobiles defy the outside compact proportions of the vehicles. But it is by no means owing to the magical paradox of the genie's lamp that automotive designers have managed to provide roomy trunks for relatively small-sized vehicles. For the most part, design achievement is simply the result of lowering the undercarriage in the vicinity of the trunk, raising the rear deck, and positioning the trunk lid to open essentially over the trunk. In effect, the trunk well is deepened.
The structured spaces of modern automobile trunk designs provide ample volumes into which heavy and bulky articles may be arranged. But, without the help of Aladdin's genie to load and unload the bulky articles, the advantageous volumes cannot be fully enjoyed. Specifically, the inconvenience of manipulating a bulky article, especially with the weight that usually accompanies bulk, is often beyond the abilities of a person given to the task of loading and unloading the heavy and bulky article, particularly a driver of small stature who is without the assistance of other passengers. A person would have to lift the article over the rear trunk wall and then gently down into the trunk to avoid damaging the article or the automobile. Thus, the driver or any other person loading a heavy or bulky article into the trunk of an automobile risks damage to the automobile and the article as well as physical strain or other injury to herself or himself.
III. Description of the Prior Art
Notwithstanding a need to provide for the special problems associated with loading and unloading heavy and bulky articles into modern deep well automobile trunks, efforts have been made to overcome the more general problems of loading and unloading automobile trunks. For example, U.S. Pat. No. 3,726,422, issued to Zelin, discloses a luggage rack that may be inserted into the rear of a station wagon body. Although the rack may be securely mounted above the floor or folded seats of the station wagon, it can be easily released to be taken out of the wagon. The rack includes a carriage which slides on a rack support through the rear door of the station wagon. By this means, the carriage can be brought to an extended position for placing and arranging luggage on and unloading luggage from the carriage. The carriage then can be slid back as the rack is brought to a retracted position within the station wagon.
The device has the obvious limitation of being structured for use in station wagons. This limitation precludes its use in the trunk of a vehicle where articles are to be let down into the trunk, rather than slid horizontally across the vehicle floor. Accordingly, the Zelin device operates as a disadvantage when compared to the present invention, considering the particular use for which the present invention is intended.
U.S. Pat. No. 2,091,069 and U.S. Pat. No. 2,094,401, both issued to C. Girl, disclose loading and unloading devices for the rear storage compartments of automobiles that are not station wagons, but the devices are nevertheless analogous in the Zelin device. All of the devices are essentially carriers that ride rail channels fixedly mounted to the platforms of vehicle luggage compartments. By manipulation readily available to a person desiring to load or unload an article strapped to the carrier of either of the Girl devices, the carrier is brought rearwardly from a position under the seat of the vehicle to the area under the trunk lid where it can be more easily loaded or unloaded by a person from either side of the vehicle.
Analogous to the shortcoming of the Zelin device, the relative greater ease and convenience of loading and unloading afforded by either Girl device, over the difficulty of reaching forwardly through the trunk to the area under the seat, falls short of providing a means of easily loading down into the well of a car trunk. Loading a cart or the like still would require having to bend over to lift a weight up from the floor of the trunk or the platform on the floor of the trunk, having to raise weight to the elevation at which it will sit on the cart or the like, and having to transport the weight to the cart. Aside from this important shortcoming, Girl also teaches that the devices must be fixedly mounted on the vehicle which adversely affects the portability of the devices.
U.S. Pat. No. 4,221,528, issued to Gordos, discloses a lifting device made up of a plurality of channel segments attached to the interior surfaces of the trunk lid of a passenger car, a bar that may be slid into the channel segments to project telescopically therefrom, and a block and tackle mechanism, together with a canvas or net sling, attached to the telescoped end of the bar. The block and tackle mechanism, together with the canvas or net sling, may be used to withdraw a heavy object located below the bar. The device further utilizes arm braces provided at the lateral edges of the trunk to transfer the load imposed on the trunk lid by the bar and channel arrangement to the body of the automobile as a triangulating arrangement.
This device calls for extensive modification of the interior of the trunk lid, but as a more significant disadvantage, the device depends on means beyond the invention disclosed by Gordos to lift or lower the heavy object from or to the floor of the trunk.
U.S. Pat. No. 2,890,908, issued to McLean et al., discloses a luggage compartment construction for vehicle bodies wherein a luggage compartment platform is a part of the unitary structure of a deck lid assembly that may be vertically elevated to a position permitting sidewise access to the platform underneath the trunk lid. The elevated platform provides greater ease of loading and unloading than at its unelevated position, which is closer to a standard elevation for a luggage compartment platform as the floor of the luggage compartment.
The McLean et al. elevating mechanism for the deck lid assembly is made up of a pair of laterally spaced apart scissors structures, each scissors structure with two legs pivotal with respect to one another about a pivot axis at the crossing of the two legs, and a jack screw assembly which actuates the pivoting. The pivot axis extends along a rod connecting the two structures; each leg is secured at one of its two ends to the underside of the platform and, at the other, to the vehicle structure. As the legs of each scissors approach becoming parallel in a vertical direction, the platform is elevated and, as they approach becoming parallel in a horizontal direction, the platform is lowered. The screw jack assembly includes a remotely operable reversible electrical motor. The structure is operated by remotely switching on the motor, preferably from the vehicle instrument panel, to rotate the screw of the jack in the direction that draws the legs of the structures toward becoming vertically parallel, thus elevating the platform, or to rotate the screw jack in a direction that draws the legs of the structures toward becoming horizontally parallel, thus lowering the platform.
Notwithstanding the elevated platform of the McLean et al. apparatus, there is still, in accordance with the teaching of McLean et al., the requirement that a person unloading or loading the platform bend over the side fenders of the vehicle to reach the article. Furthermore, McLean et al. does not teach or suggest means of translating the weight from the platform to a cart or the like. It is also the case that McLean et al. teaches that the apparatus, as well as the motor, are to be bolted or otherwise fixedly connected to the vehicle.
By far, the most advantageous apparatuses heretofore invented as a means of unloading heavy articles, from the standpoint of portability and presentment to a position for transference to a cart or the like, are disclosed in U.S. Pat. No. 4,251,178 (the '178 apparatus) and U.S. Pat. No. 4,604,022 (the '022 apparatus), both issued to Bourgraf. The Bourgraf apparatus are particularly adapted to unloading business machines and the like and are to be used in conjunction with a business machine cart for transporting and demonstrating the business machines.
The apparatus of the '178 patent, in particular, is a cart that has a wheel section and a handle section. The handle section is formed of a spaced apart pair of track along which a carriage for mounting a business machine is adapted to travel down to the foot of the cart. The foot of the cart is constructed like the platform of a dolly. A trunk loading attachment is provided that is comprised of a track-forming frame extension adapted to be connected to the upper end of the handle section, a base plate that is adapted to be positioned in the trunk, and an adjustable pivot support which mounts the base plate and to which the track-forming frame extension is pivotably mounted so that the carriage can be pushed up from the trunk, as it travels on the track of the frame extension, to the handle of the cart and down to the foot of the cart or unloading.
The '022 apparatus is a lifting mechanism to be placed in the trunk of a vehicle. There is a lift platform that is movable from a storage position within the trunk to an elevated position in which the lift platform projects outwardly from the trunk. The platform is raised by a lever mechanism that may be powered, according to this limited teaching, by a gas spring. The lift mechanism may be used with or without a cart.
While both of the Bourgraf apparatuses have portability as an object, only the lift mechanism of the '022 patent does not require it to be fixedly mounted in the trunk. The lift mechanism of the '022 patent also has the advantage of a power assist for lifting an article from the trunk. With regard to this latter advantage, however, the power assist disclosed in the '022 patent is not as easily controllable as the electric motor of the present invention and calls for an energizing means other than as provided in the standard power package of most automobiles.
IV. Objects of the Invention
Accordingly, it is the primary object of the present invention to provide a lift mechanism that can carry a heavy and bulky article over the rear wall of an automobile trunk from a cart or the like, lower the article down into the trunk so that the lid can be closed, subsequently lift the article up out of the trunk when the lid is open, and translate the article back over the rear wall to be presented for loading onto a cart or the like.
It is the further object of this invention to provide a lift mechanism that is power-operated at least to perform the lifting and lowering operations involved in loading and unloading heavy or bulky articles into and out of an automobile trunk.
Still further, it is an object of the invention to provide a power-operated lift and presenting mechanism for automobile trunks that is portable so that it can be carried to the rear wall of an automobile trunk, lifted up and put into the trunk, and made ready to perform the task of lifting and lowering a heavy and bulky article and translating the artile over the rear wall of the trunk.
An additional object of the invention is to provide a power-operated lift and presenting mechanism, for automobile trunks, made up of a combination of easily assembled and readily available parts, including a commercially available scissors mechanism that can be used to lift and lower a heavy or bulky article.
V. Summary of the Invention
In accordance with the present invention, a power-operated lift and presenting mechanism has a base adapted to be seated on the floor of the trunk of an automobile. A carriage includes a rigid, generally rectangular upper structure that is disposed parallel to and in spaced relationship with the base.
The upper structure of the carriage is essentially made up of interconnecting structural beams, including two longitudinal beams and two transverse beams. The two longitudinal beams extend between the two transverse beams, with the two transverse beams extending between and beyond their connections with the longitudinal beams. Also extending between and connected to intermediate portions of the two longitudinal beams is a bearing plae. Two drawer slide assemblies, each having a sliding channel which rides on ball bearings within a guide chanel, extend parallel to the transverse members, each of which is connected to a respective transverse beam. The sliding channel may be moved back and forth within the guide channel so that it moves from a position in which it is congruent to the guide channel to a position in which it extends from the guide channel.
The carriage also includes a lower structure made up of four structural columns of substantially equal length. All of the structural columns are perpendicular to the base. Each of the structural columns is rigidly connected to the upper frame proximate to a respective juncture of longitudinal and transverse members. Thus situated, the lower structure is adapted to vertically space the upper frame from the base and to transfer a load borne by the upper frame to the base.
A platform has a generally rectangular outer perimeter and a rigid frame that includes two generally parallel longitudinal members, two generally parallel outer transverse members, and two generally parallel inner transverse members. The outer transverse members are perpendicular to the two longitudinal members and are connected to the two longitudinal members at the extremities thereof to form the generally rectangular outer perimeter of the platform. The two inner transverse members are also perpendicular to the two longitudinal members, but are connected to the two longitudinal members at intermediate portions thereof to form a generally inner rectangular perimeter. Each more adjacent outer transverse member and inner transverse member form with end portions of the longitudinal members a generally rectangular wing perimeter adjacent the inner perimeter and to either transverse side thereof. A recessed floor is connected to the underside of the two longitudinal members and the two inner transverse members to cover the area within the generally rectangular inner perimeter. Two elevated floors are disposed over the area within the generally rectangular wing perimeters. Each elevated floor is connected to the top side of the two longitudinal members, the outer transverse member, and the inner transverse member.
The platform has a transverse facing plates rigidly edge-mounted to each inner transverse member. Each transverse facing plate extends the length of the inner transverse member and projects downwardly from the inner transverse member. The transverse facing plate are rigidly mounted adjacent to the sliding channels of the drawer assemblies. As a consequence, the platform is movable between a retracted position in which the sliding channels are generally congruent with the guide channels which are rigidly attached to the upper structure of the carriage and a presenting position in which the sliding channels extend substantially out from the guide channels and the carriage.
The scissors mechanism of the power-operated lift and presenting mechanism is a scissors jack that is connected between the base and the lift carriage by being bracketed to the base and to the bearing plate of the lift carriage. The scissors jack has a jack screw that is pivotal about its axis of extension. A pair of transversely spaced apart scissors structures are operably connected to the jack screw so that, when the jack screw pivots in a first rotational direction, the scissors structures expand along a direction perpendicular to the upper structure and the base, thereby separating the upper structure from the base, and, when the jack screw pivots in a second rotational direction, the scissors structures expand in a direction parallel to the base and the upper structure of the carriage resulting in a decrease of the distance between the upper carriage and the base.
The jack screw is operably connected to the drive shaft of a reversible electric motor by means of a drive belt trained around pulleys on the drive shaft and the jack screw, respectively. A switch actuates the motor to pivot the drive shaft in one rotational direction, when the platform is to be raised, and for actuating the motor to pivot the drive shaft in an opposite direction when the platform is to be lowered.